Thanks for the info. I just did some extra reading on the D3 and D3s and of course you are right. The D3s is an upgraded sensor over the D3 (though the D3 is 4 yrs newer than the D70).

At this point I think I may just get a new lens and wait a bit on the body. It looks like I may be just in the middle of some changes on the Nikon bodies and it may be worth waiting just a bit. I would love to pick up a D3s but it's just too expensive at this point for me.

Perhaps in the next 18-24 months the D600 issues will have been cleared up or a new prosumer class body will arrive with 8fps shooting capability and ISO performance of the D600

Regarding the Canon line, the 6D frame rate of 4.5 is just not high enough for me. I currently have 3.0fps with the D70 and even with 50% boost in frame rate I don't feel it would be enough to catch the image. I really want ~6fps or higher. The 5DmkIII is great, but just too expensive. If I'm going to spend $3.5k, I'll just pony up and get the 3Ds used instead.